Check for [] operator

Question

How do I check whether an object supports [] operation in Python? I think of something like the following:

if supports(obj, ?[]?):
    print("Supports")  

Answer 1

You don't "check for support". You just use it:

try:
    a = obj[whatever]
except TypeError:
    # whatever your fall-back plan is when obj doesn't support [] (__getitem__) 

Writing your own isinstance is always the wrong thing to do. A new type that doesn't inherit from the collections ABC classes can still have the right behavior. Duck Typing means you can never rely on isinstance.

Writing your own hasattr test merely duplicates Python's internal checking that raises the exception. Since Python must do the test, why duplicate that?

Finally, "I think that with exception handling this code will be less readable." Is false. The Pythonic principle, accepted by many experienced Python programmers is that it's Easier to Ask Forgiveness That to Ask For Permission.

The language is designed to do this with exceptions.